Renaming of Hostname in HACMP Cluster

We have 4 node HACMP Cluster running with 5.4 version. Out of this 4 nodes, 3 nodes are active and 1 is standby node. In one of the active node I want to rename the hostname and IP address (this IP needs to modify in resource group) of the node. Can anyone please let me know how we can do it? Do we require downtime for all the nodes or need downtime for only the node where we are doing the changes?

<quote>
When someone wants to become a pilot, they can't jump into a plane and try
to take off. It's not that flying is inherently hard, but it requires a
foundation of understanding. Clustering is the same in this regard; there
are many different pieces that have to work together just to get off the
ground.

You *must* have patience.

Like a pilot on their first flight, seeing a cluster come to life is a
fantastic experience. Don't rush it! Do your homework and you'll be on your
way before you know it.
</quote>

...and...

<quote>
Even the most basic cluster requires several pieces be in place and working
together. If you try to rush by ignoring pieces you think are not
important, you will almost certainly waste time. A good example is setting
aside fencing <https://alteeve.ca/w/Fencing>, thinking that your test
cluster's data isn't important. The cluster software has no concept of
"test". It treats everything as critical all the time and *will* shut down
if anything goes wrong.

Take your time, work through these steps, and you will have the foundation
cluster sooner than you realize. Clustering is fun *because* it is a
challenge.
</quote>

Looking back through the history of your questions regarding HACMP
essentials I wondered...
...is it maybe time to follow some studies or courses to boost your own
knowledge ?